Method for upgrading a dial indicator to provide remote indication capability

ABSTRACT

A dial indicator, method, and kit for upgrading a dial indicator to provide both local visible and remote indication of a measured physical parameter is provided. A magnetic rotary pointer is provided by coupling a magnet to a pointer, or by providing a replacement pointer having an integral magnet, so that the magnetic rotary pointer is rotatable in response to a change a measured physical parameter. A potentiometer is magnetically coupled to the magnetic rotary pointer, and is fastened to a front side of the dial indicator.

Related Applications

[0001] This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/282,054, entitled Capacity Measurement DeviceFor A Liquid Storage Tank, filed Apr. 7, 2001.

BACKGROUND OF THE INVENTION

[0002] (1) Field of the Invention

[0003] The present invention relates generally to a dial indicator, andmore particularly relates to a dial indicator capable of providing bothlocal visible indication and remote indication of a physical parameter.

[0004] (2) Background Information

[0005] Dial indicators (also variously referred to as dial gauges,indicator gauges, dial faces, and/or analog gauges) are commonly used toindicate a host of physical parameters such as temperature, pressure,electrical properties, liquid levels, among others. For example, liquidstorage tanks for fuel, oil, propane, natural gas, and ammonia typicallyinclude a dial indicator attached thereto for providing an on-site,visible reading of the liquid level (i.e., the percentage of the totaltank volume occupied by the liquid. For many applications it isdesirable, both for convenience and economic factors, to have both localvisible indication and remote indication of the above-mentioned physicalparameters. For example, it is generally necessary for a user to beaware of the quantity of remaining liquid in a liquid storage tank, suchas for determining when refilling is necessary. In some industrialapplications, in which large numbers of tanks are employed, remoteindication may be desirable. However, local visual indication may alsobe desirable, for example, to monitor the filling operation.

[0006] Examples of indicators providing both on-site and remoteindication are disclosed in U.S. Pat. Nos. 4,554,494 to Howeth;4,911,011 to Fekete, et al.; 4,975,687 to Murphy, Jr. et al.; 4,987,400to Fekete; 5,305,639 to Pontefract; and 5,357,815 to Williamson; each ofwhich is fully incorporated by reference herein. Fekete, et al., in U.S.Pat. Nos. 4,911,011 and 4,987,400, for example, disclose a dialindicator having a magnetically driven voltage divider built into thedevice behind the dial face for providing an electrical indication ofliquid level in a liquid storage tank.

[0007] The above systems tend to be complex and therefore may berelatively expensive. Further, for some applications for which bothlocal and remote indication are desirable, it may not be economicallyfeasible to replace the existing gauge. Further still, for manyapplications, dial indicators providing for both local visual and remoteindication may not be commercially available. Therefore, there exists aneed for a relatively simple and inexpensive dial indicator thatprovides for both onsite and remote indication. There also exists a needfor a relatively simple and inexpensive method for upgrading aconventional dial indicator (which provides only visual indication) toinclude the capability of providing remote indication.

SUMMARY OF THE INVENTION

[0008] One aspect of the present invention includes a method forupgrading a dial indicator to provide both local visible and remoteindication of a physical parameter. The method includes providing thedial indicator with a magnetic rotary pointer, the magnet rotary pointerbeing rotatable in response a change in the physical parameter. Themethod further includes magnetically coupling a potentiometer to themagnet, the potentiometer being magnetically adjustable, wherein arotation of the magnet causes a change in the electrical output of thepotentiometer and fastening said potentiometer to a front side of thedial indicator. In variations of this aspect, the magnetic rotarypointer is provided by securing a magnet to a pre-existing rotarypointer, or by replacing the pre-existing rotary pointer with areplacement rotary pointer having a magnet integrated therewith. Inanother variation of this aspect the dial indicator is mounted to aliquid storage tank and the potentiometer is fastened to the dialindicator by interposing it between a transparent bracket and atransparent cover, and fastening the bracket to the dial indicator.

[0009] In another aspect, this invention includes a kit for upgrading adial indicator to provide both local visible and remote indication of aphysical parameter. The kit includes a magnet, sized and shaped forcoupling to the dial indicator in a manner in which the magnet rotatesin response to a change in the measured physical parameter, amagnetically adjustable potentiometer, and a mounting assembly thatincludes a bracket, sized and shaped for fastening the potentiometer tothe dial indicator. In variations of this aspect, the magnet may besized and shaped for being secured to a pre-existing rotary pointer ofthe dial indicator, or the magnet may include a replacement rotarypointer.

[0010] In yet another aspect, this invention includes a dial indicatorfor providing a local visible and a remote display of a liquid level ina liquid storage tank. The dial indicator includes a magnetic rotarypointer which is rotatable in response to a change in the liquid levelin the tank. The dial indicator further includes a magneticallyadjustable potentiometer including a voltage divider and at least twoelectrical connectors, the potentiometer being magnetically coupled tothe magnetic rotary pointer so that rotation of the magnetic rotarypointer causes a change in the electrical output of the potentiometer.The potentiometer is mounted to a front side of the dial indicator by atransparent bracket. In variations of this embodiment, the magneticrotary pointer includes a rotary pointer having a magnet securedthereto, or includes a replacement rotary pointer having a magnetdisposed integrally therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective schematic representation of a fuel tankassembly including the present invention;

[0012]FIG. 2 is a schematic, front view representation of a prior artdial indicator of the type useful in conjunction with the presentinvention;

[0013]FIG. 3 is a schematic, front view representation one embodiment ofa dial indicator configuring according to the present invention;

[0014]FIG. 4 is an exploded perspective schematic view of the dialindicator of FIG. 3;

[0015]FIG. 5 is a view similar to that of FIG. 4, of another embodimentof this invention;

[0016]FIG. 6 is a flow chart representation of one embodiment of themethod of this invention; and

[0017]FIG. 7 is a view similar to those of FIGS. 4 and 5, of anotherembodiment of this invention.

DETAILED DESCRIPTION

[0018] Referring to FIG. 1, a liquid storage tank assembly 100 includingthe present invention is illustrated. Assembly 100 includes a dialindicator 40 mounted to a liquid storage tank 10. Dial indicator 40provides a local visible indication of the liquid level in tank 10 andis coupled 105 to a remote display 110 for also providing remoteindication of the liquid level in tank 10. Dial indicator 40 may becoupled 105 to remote display 110 by any known link, such as a directelectrical connection (e.g., one or more wires), a telephone linkincluding a modem and a hardwired telephone line or a cellular telephonelink, or a radio frequency communications link.

[0019] Referring now to FIGS. 3-5, a dial indicator 40 constructedaccording to the principles of the present invention is shown. Brieflydescribed, the present invention includes a dial indicator 40 thatprovides for both local visible and remote indication of a physicalparameter, such as temperature, pressure, liquid level and the like.Dial indicator 40 is particularly useful for monitoring the liquid levelin large liquid storage tanks (e.g., liquid storage tank 10 in FIG. 1)in which liquefied natural gas, liquid propane, or liquid ammonia isstored. Dial indicator 40 includes a potentiometer 46 fastened to afront side thereof (e.g., to a transparent cover 27). Potentiometer 46is magnetically coupled to a magnet 30, 30′, which is coupled to therotary dial pointer 22 in a manner allowing the magnet 30 to rotate withthe pointer 22 in response to a change in the measured physicalparameter. This invention also includes a method for retrofitting aconventional dial indicator to include the capability of providingremote indication, in which a magnet 30, 30′ is coupled to the rotarydial pointer 22 and a potentiometer 46 is magnetically coupled to magnet30, 30′ and fastened to a front side of the dial indicator 40.

[0020] The present invention is advantageous in that it provides arelatively simple and inexpensive dial indicator capable of providingboth local and remote indication of a physical parameter. Further, thisinvention provides a relatively simple and inexpensive method forupgrading a conventional dial indicator of substantially any type toinclude the capability of providing remote indication of a physicalparameter. Additional advantages of this invention are discussedhereinbelow along with a more detailed description of the invention.

[0021] Referring now to FIG. 2, a conventional dial indicator 20typically includes a housing 21 having a faceplate 24 with indicia 25printed thereon. A rotary dial pointer 22 coupled to a conventionalsensor mechanism (not shown) provides for a visible indication of themeasured physical parameter. Dial indicator 20 also typically includes atransparent cover 27 (see FIGS. 4-5) on the front face thereof.

[0022] Referring again to FIGS. 3-5, embodiments of a dial indicator 40including the present invention are illustrated and described in moredetail. Referring initially to FIG. 3, dial indicator 40 is similar todial indicator 20 in that it includes a housing 21 having a faceplate 24with indicia 25 printed thereon and a rotary pointer 22 for providing avisible indication of the measured physical parameter. Rotary pointer 22may be any type that is typically used in gauges known in the art, suchas shown and described in U.S. Pat. No. 4,975,687 to Murphy, Jr. et al.Dial indicator 40 further includes a potentiometer 46 (described ingreater detail hereinbelow), typically having at least two electricalconnectors 47 coupled thereto for providing an electrical outputindication of the measured physical parameter. Potentiometer 46 istypically fastened to the front side of dial indicator 40 by a bracket42, which may be fastened to housing 21 using conventional fasteners 43(e.g., screws, bolts or pins threaded or otherwise inserted into one ormore recesses 44 (FIGS. 4-5) in housing 21). The term “front side”, asused herein, shall refer to the side of the dial indicator from which avisual reading may be obtained. Bracket 42 is typically, but notnecessarily, constructed of an optically transparent material, such as arelatively clear plastic sold under the trademark PLEXIGLAS® (Rohm &Haas Company, Philadelphia Penn.), or under the trademark LEXAN®(General Electric Company, Pittsfield Mass.). The bracket may also befabricated from various opaque materials, such as aluminum or stainlesssteel. The bracket 42 is fastened to the front side of potentiometer 46and screwed into housing 21.

[0023] Referring now to FIGS. 4 and 5, dial indicators 40 and 40′ ofthis invention further include one or more magnets 30, 30′ physicallycoupled to rotary pointer 22. Magnet(s) 30, 30′ may be any type havingnorth 30N, 30N′ and south 30S, 30S′ poles and are typically relativelysmall in order to be easily installed in the dial indicator 40, 40′. Inembodiment 40 (FIG. 4), a horseshoe magnet 30 is looped around thebackside (i.e., opposite to front side) of the rotary pointer 22 and isdisposed with its poles 30N, 30S oriented towards the front side of thedial indicator 40. In another embodiment indicator 40′ (FIG. 5) includesa magnet 30′, in which opposite sides or ends have opposite poles 30N′,30S′, and which is physically coupled to the rotary pointer e.g., bygluing it to the front side thereof.

[0024] Magnet 30′ may be a bar magnet, or may be a thin horseshoe magnet(similar in size and shape to a coin, having both poles 30N′ and 30S′ onthe same flat side thereof). Such a magnet may be provided with acentral hole (not shown) through which a rivet or similar fastener mayextend to attach the magnet to the pointer at its axis of rotation.Still further, a pair of magnets 30″, each having poles 30N′ and 30S′ onopposite sides thereof, may be provided as shown in FIG. 7. Thesemagnets 30″ may be fastened to the pointer (e.g., using glue), withopposite poles facing the potentiometer 46. Use of multiple magnets 30″may be particularly useful in retrofit applications, as discussed ingreater detail hereinbelow. As shown, multiple magnets 30″ may bebalanced about the axis of rotation of pointer 22 (e.g., magnets 30″ maybe disposed on opposite sides of the axis of rotation of the pointer) tohelp prevent uneven or excessive wear of the pointer mechanism.Alternatively, in the event it is desirable to dispose one or moremagnets 30, 30′, 30″ assymetrically about the axis of rotation, one ormore weights may be applied to the pointer 22 where desired tocounterbalance the magnet(s). Magnet(s) 30, 30′, 30″ are thus coupled torotary pointer 22 in a manner that allows them to rotate with thepointer 22 in response to a change in the measured physical parameter.As a still further alternative, a replacement pointer 22 may beprovided, having magnet(s) 30′ 30″ integrally disposed therewith, suchas for inclusion in a kit as discussed hereinbelow. For example,replacement pointer 22 may include a magnet fabricated in the form of arotary pointer.

[0025] Potentiometer 46 may be any that may be adjusted by the rotationof a magnetic field (hereafter referred to as magnetically adjustable)and is magnetically coupled to magnet 30, 30′, 30″. A change in theorientation of rotary pointer 22 therefore changes the electrical outputof potentiometer 46. As mentioned hereinabove potentiometer 46 typicallyincludes at least two electrical connectors or ports (e.g., wires),which may be connected to a remote display (e.g., remote display 110).Alternatively, as described above, the electrical output may be used incombination with a radio frequency or other wireless communicationdevice to provide for remote monitoring. Further, potentiometer 46typically includes a diameter less than about half that of dialindicator 40 in order not to obscure visual reading of the indicator 40.In one embodiment, potentiometer 46 may be a single-turn, magneticallyadjustable voltage divider. In another embodiment, potentiometer 46 mayinclude another dial indicator having an internal magneticallyactuatable voltage divider (e.g., the Twinsite® potentiometer (P/NP5928S02669) as manufactured and sold by Rochester Gauges, Inc., Dallas,Tex.).

[0026] This invention may also include a kit for upgrading a prior artdial indicator 20 to provide both local visible and remote indication ofa physical parameter. The kit may include one or more magnets 30, 30′,30″ sized and shaped for coupling to a rotary pointer 22 so that themagnet rotates with the rotary pointer 22 in response to a change in themeasured physical parameter. (The kit may alternatively include areplacement (i.e., substitute) pointer 22 having one or more magnetsintegrally disposed thereon, as mentioned hereinabove.) The kit may alsoinclude a magnetically adjustable potentiometer 46 and a mountingassembly that includes a bracket 42, sized and shaped for fastening thepotentiometer 46 to the dial indicator 20, and at least one fastener 43.The kit may further include a remote display 110 for providing remoteindication of the measured physical parameter. The kit may still furtherinclude components necessary for linking the potentiometer 46 to theremote display, such as electrical wire, telephone wire, a modem, aradio transmitter/receiver, and the like. As mentioned hereinabove, useof multiple magnets 30″ may be advantageous in retrofit applications,since the magnets 30″ may be fastened to the pointer 22 withoutrequiringremoval or disassembly of the pointer 22, to provide relativelysimple and quick installation.

[0027] Referring now to FIG. 6, an embodiment of the method of thisinvention is described in more detail. At 52 a conventional dialindicator 20 is used or provided. Dial indicator 20 may be configured tomonitor any of numerous physical parameters such as temperature,pressure, liquid level, and the like. In one useful embodiment, a dial20 indicator mounted to a liquid storage tank (e.g., a liquefied naturalgas, a liquid propane, or a liquid ammonia storage tank) is utilized. At53, the dial indicator cover 27 may optionally be removed. It may befurther necessary to remove the rotary pointer 22 and its associatedbearing assembly. At block 54 one or more magnets 30, 30′, 30″ (FIGS. 4,5, and 7) are physically coupled to the rotary pointer 22 in a mannerthat allows them to rotate with the pointer 22, as discussedhereinabove. At 55 the cover 27 may be refastened to the dial indicator20. For some applications it may be necessary to modify (e.g., bend orcut) the cover 27 in order to prevent it from interfering with theinstalled magnet(s) 30, 30′. At 56, a potentiometer 46 is disposed onthe front side of dial indicator 20 (e.g., on the front side of thecover 27) in a manner enabling it to be magnetically coupled to themagnet(s) 30, 30′. The potentiometer 46 is then fastened 58 to the dialindicator 20 using any known fastening means. For example, in oneembodiment, a transparent bracket is disposed on the front side of thepotentiometer 46 and screwed into the dial indicator housing 21 in orderto hold the potentiometer 46 securely in place.

[0028] The modifications to the various aspects of the present inventiondescribed hereinabove are merely exemplary. It is understood that othermodifications to the illustrative embodiments will readily occur topersons with ordinary skill in the art. All such modifications andvariations are deemed to be within the scope and spirit of the presentinvention as defined by the accompanying claims.

What is claimed is:
 1. A method for upgrading a dial indicator toprovide both local visible and remote indication of a physicalparameter, said method comprising: providing the dial indicator with amagnetic rotary pointer, said magnet rotary pointer being rotatable inresponse to a change in the physical parameter; magnetically coupling apotentiometer to said magnet, said potentiometer being magneticallyadjustable, wherein a rotation of said magnet causes a change in theelectrical output of said potentiometer; and fastening saidpotentiometer to a front side of the dial indicator.
 2. The method ofclaim 1, wherein said providing is accomplished by securing a magnet toa rotary pointer of the dial indicator.
 3. The method of claim 1,wherein said providing is accomplished by replacing a rotary pointer ofthe dial indicator with a replacement rotary pointer, said replacementpointer having a magnet disposed integrally therewith.
 4. The method ofclaim 1 wherein the dial indicator comprises a liquid level indicatorfor a storage tank.
 5. The method of claim 1 wherein the dial indicatoris mounted to a liquid storage tank.
 6. The method of claim 5 whereinsaid storage tank comprises a natural gas storage tank.
 7. The method ofclaim 5 wherein said storage tank comprises a liquid propane storagetank.
 8. The method of claim 5 wherein said storage tank comprises aliquid ammonia storage tank.
 9. The method of claim 1 wherein saidmagnet comprises a plurality of magnets disposed in spaced relationalong said rotary pointer.
 10. The method of claim 9, wherein saidplurality of magnets comprises a pair of magnets disposed on said rotarypointer, on opposite sides of an axis of rotation of said pointer, saidpair of magnets being disposed in opposite orientation relative to oneanother so that opposite poles face away from the dial indicator. 11.The method of claim 1 wherein said magnet comprises a bar magnet
 12. Themethod of claim 11 wherein said magnet is coupled to a front side ofsaid rotary pointer.
 13. The method of claim 1 wherein said magnetcomprises a horseshoe magnet.
 14. The method of claim 11 wherein saidcoupling comprises looping said magnet around a backside of said rotarypointer.
 15. The method of claim 1 wherein said potentiometer comprisesa magnetically adjustable voltage divider.
 16. The method of claim 1wherein said potentiometer comprises a single-turn potentiometer. 17.The method of claim 1 wherein said potentiometer comprises an other dialindicator, said other dial indicator including a voltage divider, saidother dial indicator having a diameter less than about half that of thedial indicator.
 18. The method of claim 1 wherein said potentiometercomprises at least two electrical connectors.
 19. The method of claim 1further comprising coupling said potentiometer to a wirelesscommunication device.
 20. The method of claim 1 wherein saidpotentiometer is fastened to a transparent cover.
 21. The method ofclaim 1 wherein said fastening said potentiometer comprises interposingsaid potentiometer between a bracket and a transparent face plate, andfastening said bracket to the dial indicator.
 22. The method of claim 21wherein said bracket comprises an optically transparent material. 23.The method of claim 22 wherein said optically transparent materialcomprises plastic.
 24. The method of claim 1, wherein said physicallycoupling further comprises: removing a cover from the front face of thedial indicator; and refastening said cover to the front face of the dialindicator.
 25. A kit for upgrading a dial indicator to provide bothlocal visible and remote indication of a physical parameter, said kitcomprising: a magnet, sized and shaped for coupling to the dialindicator in a manner wherein said magnet rotates in response to achange in the measured physical parameter; a magnetically adjustablepotentiometer; and a mounting assembly including a bracket sized andshaped for fastening said potentiometer to the dial indicator.
 26. Thekit of claim 25, wherein said magnet is sized and shaped for beingsecured to a rotary pointer of the dial indicator.
 27. The kit of claim25, wherein said magnet comprises a replacement rotary pointer.
 28. Thekit of claim 25 wherein said magnet comprises a horse shoe magnet. 29.The kit of claim 25 wherein said magnet comprises a bar magnet.
 30. Thekit of claim 25 wherein said potentiometer comprises a single-turnvoltage divider.
 31. The kit of claim 25 wherein said potentiometercomprises an other dial indicator, said other dial indicator including amagnetically actuatable voltage divider, said other dial indicatorhaving a diameter less than about half that of said dial indicator. 32.The kit of claim 25 wherein said bracket comprises an opticallytransparent material.
 33. The kit of claim 32 further comprising aremote display.
 34. A dial indicator for providing both local visibleand remote display of liquid level in a liquid storage tank, said dialindicator comprising: a magnetic rotary pointer, said magnet rotarypointer being rotatable in response to a change in the liquid level inthe tank; a magnetically adjustable potentiometer including a voltagedivider and at least two electrical connectors, said potentiometer beingmagnetically coupled to said magnetic rotary pointer wherein a rotationof said magnetic rotary pointer causes a change in the electrical outputof said potentiometer; said potentiometer being mounted to a front sideof said dial indicator by a transparent bracket.
 35. The dial indicatorof claim 34, wherein said magnetic rotary pointer comprises a a rotarypointer of the dial indicator having a magnet secured thereto.
 36. Thedial indicator of claim 34, wherein said magnetic rotary pointercomprises a replacement rotary pointer, said replacement pointer havinga magnet disposed integrally therewith.
 37. The dial indicator of claim34 wherein said potentiometer comprises an other dial indicator, saidother dial indicator including a voltage divider.
 38. The dial indicatorof claim 34, wherein said potentiometer comprises an other dialindicator, and said other dial indicator has a diameter less than abouthalf that of said dial indicator.